On-line restoration for turbulence degraded video in nuclear power plant reactors

Abstract : This article deals with video inspection of nuclear plant reactor after fuel reloading. During these underwater inspections, the fuel assemblies’ heat generates turbulence effect that sensitively degrades the video quality. An on-line restoration algorithm is proposed here. It consists of two steps. A temporal infinite impulse response filter is first used to get a stabilized but blurry video. A second spatial Wiener deconvolution filter is then used to estimate the video which would have been observed without turbulence. This second filter is based on a probabilistic model of the turbulence impact on the observed video. An on-line prototype, based on this algorithm and its straightforward extension to a moving camera (translation), has been successfully tested on several power plants.